"Warty Stigmaria." (_Stigmaria ficoides_, Brongniart. _Phytolithus verrucosus_, Martin's Petrificata Derbiensia, Pl. II. _Ficoidites verrucosus_, of Artis.) In this species of Stigmaria the tubercles vary considerably in size, and give a verrucose, or warty, aspect to the surface. The specimen figured on a small scale, fig. 2, and a portion of the natural size, fig. 1, was between five and six feet in length, and four inches in diameter. A groove visible on the external surface indicates the inner axis, which by compression has been pressed from its natural central position; see fig. 2, A, B, C, D: figs. 6, 7, 8, 9, show in the corresponding transverse sections the position of this body. The mode of attachment of the rootlets to the tubercle on the main root, is represented fig. 5. Fig. 3, exhibits the characters of the two kinds of variolæ, or tubercles. When Dr. Buckland's Bridgewater Essay was published, the true nature of these fossil remains was unknown. It was supposed by Messrs. Lindley and Hutton, that the original was an aquatic plant, having a short dome-shaped trunk, from which radiated numerous long horizontal branches; and that when the plant was perfect, and the branches floating on the water, its appearance resembled that of an Asterias.[20] This dome-shaped trunk is now known to be merely the base of the stem of the tree. See _Supplementary Notes_, art. _Stigmaria_. [Footnote 20: Dr. Buckland's Bridgewater Essay, vol. ii. p. 95.] [Illustration: Plate XXIII.] PLATE XXIII. "Great Stigmaria." (_Stigmaria ficoides_, of Brongniart. _Ficoidites major_, of Artis.) The fossil here represented is a fragment of a Stigmaria having larger tubercles than the species previously described. The tubercles are oval at the base, somewhat compressed, longitudinally farrowed at the top, with a pit in the furrow. This root is from five to six inches in diameter; the axis is seen near the compressed side, in the transverse section at the bottom of the figure. From a sandstone quarry, near Rotherham, Yorkshire. The specimen figured by Mr. Parkinson, _ante_, Plate III. fig. 1, appears to be the fragment of a Stigmaria of this kind in ironstone: the internal axis is seen in the transverse section pressed from its natural position to near the outer surface. [Illustration: Plate XXIV.] PLATE XXIV. "Crested Aspidiaria." (_Aspidiaria cristata_, of Presl. _Sigillaria appendiculata_, Brongniart. _Aphyllum cristatum_, Artis.) The fossil here represented is part of the stem of a tree nearly forty feet long, and two feet in diameter, found imbedded in sandstone at Banktop, Yorkshire. The cicatrices of the petioles are obovate, and have a central oblong crest or ridge; the interstices form deep angular furrows.